Over-pressure protection system

• US 6,880,567 B2
• Filed: 11/01/2002
• Issued: 04/19/2005
• Est. Priority Date: 11/01/2001
• Status: Expired due to Fees

• Current Assignee: Shell Oil Company (Shell Plc)
• Original Assignee: Shell Oil Company (Shell Plc)
• Inventors: Pettitt, Mark, Klaver, Theodorus Cornelis
• Primary Examiner(s): Krishnamurthy, Ramesh
• Application Number:
  US10/494,099
• Publication Number:
  US 20040261856A1
• Time in Patent Office: 900 Days
• Field of Search: 137/461, 137/487.5, 137/557, 731/68
• US Class Current: 137/487.5
• CPC Class Codes: F16K 17/04 spring-loaded
• CPC Class Codes: F16K 37/00 Special means in or on valves or other cut-off apparatus for indicating or recording operation thereof, or for enabling an alarm to be given
• CPC Class Codes: Y10T 137/7728 High pressure cut-off
• CPC Class Codes: Y10T 137/7761 Electrically actuated valve
• CPC Class Codes: Y10T 137/8326 Fluid pressure responsive indicator, recorder or alarm

Abstract

An over-pressure protection system having a conduit section extending between a pressure reduction valve and a low-pressure fluid handling system, a shut-off valve provided with an actuator arranged in the conduit section, pressure sensors arranged one on either side of the shut-off valve in the conduit section, a safety control system that communicates with the actuator and the pressure sensors which produces a signal when it detects a high pressure in the conduit section, and a self-diagnostic system for checking the shut-off valve and the pressure sensors that communicates with the actuator, the pressure sensors and the safety control system, which self-diagnostic system produces a signal when it detects a failure in either the shut-off valve or the pressure sensors or both.

Claims

1. An over-pressure protection system comprising a conduit section extending between a pressure reduction valve and a low-pressure fluid handling system, a shut-off valve provided with an actuator arranged in the conduit section, pressure sensors arranged one on either side of the shut-off valve in the conduit section, a safety control system that communicates with the actuator and the pressure sensors and produces a signal when it detects a high pressure in the conduit section, and a self-diagnostic system for checking the shut-off valve and the pressure sensors that communicates with the actuator, the pressure sensors and the safety control system, which self-diagnostic system produces a signal when it detects a failure in either the shut-off valve or the pressure sensors or both.

2. The over-pressure protection system according to claim 1, wherein the signal is a warning signal to an operator in case of a failure.

3. The over-pressure protection system according to claim 1, wherein the signal will also cause interrupting the operation of the low-pressure fluid handling system within a predefined time.

4. The over-pressure protection system according to claim 1, wherein the self-diagnostic system is programmed to carry out, when the shut-off valve is fully open, the steps of:

measuring continuously the pressures with the pressure sensors;

calculating the pressure difference; and

giving a signal if the difference is greater than a predefined limit.

5. The over-pressure protection system according to claim 4, wherein the self-diagnostic system is further programmed to carry out the steps of:

displacing the valve body of the shut-off valve so as to start closing the shut-off valve;

recording the pressures measured by the pressure sensors upstream and downstream of the shut-off valve;

stopping displacing the valve body when the pressure difference across the shut-off valve is greater then a predefined limit and the upstream pressure is greater than the downstream pressure; and

then re-opening the shut-off valve.

6. The over-pressure protection system according to claim 4, wherein the self-diagnostic system is further programmed to carry out the steps of:

causing the actuator to displace the valve body of the shut-off valve;

comparing the displacement of the valve body and power supplied to the actuator with the expected displacement and power; and

giving a signal if either the displacement or the power is not as expected.

7. The over-pressure protection system according to claim 6, wherein displacing the valve body of the shut-off valve is done over part of the stroke of the valve body.

8. The over-pressure protection system according to claim 6, wherein displacing the valve body of the shut-off valve is done over the full stroke of the valve body.

9. The over-pressure protection system according to claim 5, wherein the self-diagnostic system is further programmed to carry out the steps of:

causing the actuator to displace the valve body of the shut-off valve;

comparing the displacement of the valve body and power supplied to the actuator with the expected displacement and power; and

giving a signal if either the displacement or the power is not as expected.

10. The over-pressure protection system according to claim 2, wherein the self-diagnostic system is programmed to carry out, when the shut-off valve is fully open, the steps of:

measuring continuously the pressures with the pressure sensors;

calculating the pressure difference; and

giving a signal if the difference is greater than a predefined limit.

11. The over-pressure protection system according to claim 3, wherein the self-diagnostic system is programmed to carry out, when the shut-off valve is fully open, the steps of:

measuring continuously the pressures with the pressure sensors;

calculating the pressure difference; and

giving a signal if the difference is greater than a predefined limit.